There should probably be multiple open-access journals (or Virtual Super-Journals) within each field, so that the competition between them keeps them honest.
Why does competition = honesty not work now then?
For that matter, what's the problem? Shitty journal articles may be annoying, but researchers aren't exactly confused by them. "This article was published in the 'western romanian journal of blood borne pathogens in pigeons?' Hmm... better take it very seriously." A huge number of crap open access journals is only a problem for people who want to see research in extremely simplistic terms. People who just want to count publications and determine who to throw money at are the ones who see it as a problem. But such people are idiots and are going to waste money no matter how you try to prevent shitty publications. And researchers are going to be able to game such systems anyway.
Saliva causes cancer, but only if swallowed in small amounts over a long period of time. -- George Carlin